I had always wanted to work in Antarctica. I believed it to be the kind of place where one would be thrust into exciting adventures as a normal part of one's daily work routine; a place, both beautiful and treacherous, where one could contribute to valuable scientific research while experiencing the utmost physical and mental challenges. I first worked in Antarctica as part of the Australian National Antarctic Research Expeditions. During the five-month summer field season in 2000/2001, I worked at Davis station (Australia's southernmost Antarctic base) on a three-year glaciology project called Structure and Dynamics of the Sorsdal Glacier. Chris Wilson, at the University of Melbourne's School of Earth Sciences, supervised the project.
Abseiling is an important part of field training for glacier travel
The objective of the Sorsdal Glacier project, spanning 2000-2003, is to produce high-resolution models of ice-dynamics that will help glaciologists understand the formation and propagation of glacier structures over time. Such models can then be used to provide valuable analogues for understanding the formation of structures that geologists commonly observe in rock outcrops (such as fold, faults, shear zones etc). Whereas rock deformation occurs at immense pressures and temperatures and is practically immeasurable as it spans geological time scales, glacier ice deforms comparatively quickly, at low temperatures, near the surface of the Earth, and can be physically measured over time intervals of days, weeks, months and years.
To monitor ice movement on the Sorsdal Glacier, the stop-and-go GPS technique has been used to repeatedly survey three grid networks comprising over 250 discrete markers strategically placed on the glacier surface. The results, based on data collected over two summer field seasons (2000/2001 and 2001/2002), show differential movement of the glacier ice ranging between 4 metres/yr and 114 metres/yr.
Apart from this, other important fieldwork has included deploying a DORIS (Doppler Orbitography and Radiopositioning Integrated by Satellites) beacon on a fast-moving section of the Sorsdal glacier. This involved mapping many of the surface structures (such as crevasses and crevasse traces) using geological methods, collecting ice-cores at selected study sites and replacing a GPS receiver at a new geodetic site in the Grove Mountains (placed by personnel from the National Mapping Division of Geoscience Australia in 2000/2001). In each of these activities I and field partner Ben Patrick Ð a glaciologist from the School of Earth Sciences at the University of Melbourne Ð found many unlooked-for adventures.
In December 2001 I recorded that for nearly half our time in the field we were restricted to living inside the confines of our rather small, though well-insulated, field hut, due to harsh weather. On several occasions violent blizzards (often katabatic winds blowing tremendous quantities of drift snow) kept us trapped indoors for up to three days at a time, during which tiresome periods of waiting I could only plan future surveys, process data and read books. The average gusts during these blizzards were 60Ð80 knots, though on one extreme occasion we experienced 100 knots. I noticed after a month of regular blizzards that the yellow paint had been stripped from a tripod leg mounted at a nearby control site, and that the exposed wood had become naturally polished through excessive bombardment with snow and grit Ð testament to the ferocious winds we were experiencing.
At our survey sites on the glacier, which are up to 15 km from our field camp and half an hour's drive by quad motorbike (we use these for expedient glacier travel), there was always the risk of exposure to sudden blizzards. For this reason we always travelled with a mountain tent, ground mat, bivouacs, down sleeping bags and VHF radios; the best strategy, though, is simply not to work in suspect weather.
I did not have the misfortune of encountering blizzard conditions on the Sorsdal Glacier, thankfully combined with avoiding crevasses, this would have been an exceedingly discomforting experience though we several times abandoned our survey work in anticipation of ill weather. Often I found there was a need to work extra hours on days of good weather to compensate for the days of bad weather. This was feasible over summer, since our latitude 68û35'S permitted 24 hour sunlight.
A glacier meltstream near the Sorsdal Glacier. Such streams greatly disrupt navigation onto the glacier
Glacier meltstreams are another phenomena that plagued our mapping efforts on the Sorsdal Glacier. These appear quite suddenly during summer as temperatures rise above zero degrees. Lasting only a few weeks before re-freezing, they form an impenetrable network of fast-flowing channels covering the glacier surface. Fording the streams with quad motorbikes, or on foot, is practically impossible. It's even more difficult carrying cumbersome survey gear.
More inconspicuous are the snow swamps that often form simultaneously with the meltstreams. These are vast areas of snow that have become extremely slushy, though they may appear firm to the unfamiliar traveller. I have chilling memories of a situation that I found myself in after completing a stop-and-go survey very late one night: Ben and I drove our quads directly into a concealed snow swamp. The quads were bogged, and since we were saturated from the waist down, we thought it better to dash the remaining distance to our field hut on foot. So, retrieving only the GPS units (containing the recently acquired data), our ice axes and a stretch of rope, we proceeded to
navigate our way by crawling and walking through nearly 100 metres of icy slush and then jogging to our field hut. We arrived feeling extremely cold and numb, but, fortunately, not frostbitten.
A quad bogged in a snow swamp - one of the many hazards of surveying in Antarctica
The following day we made an assessment of the situation, hoping to retrieve the quads using a pulley system. However, since there was no nearby stable ground from which to set up an anchor, the quads had to be flown out by helicopter. But falling into snow swamps (from my perspective) was not nearly as unnerving as working in crevassed areas, into which parts of our survey networks encroached. Navigation through these areas can be a risky exercise, especially if the crevasses are hidden by snow.
s a precaution, we always travelled roped together. We followed glacier travel protocols for which we were trained, as part of ANARE regulations, but it can be awkward donning your essential mountaineering gear and carrying technical equipment at the same time.
On one occasion I dismounted my quad to survey a nearby marker, holding the GPS antenna pole in one hand and the processor on my back, and fell straight through a snow bridge and into a crevasse. I managed to sling myself out almost instantaneously, and though I was unscathed physically, I was quite shaken. Had I continued to fall, I would probably have dropped the GPS antenna pole before the rope caught. It turns out, however, that not only had I kept hold of the survey equipment, but the antenna had maintained lock on at least five satellites, so I didn't have to re-initialise the GPS receiver (though it would have been the least of my worries!)
On another day I had an even more frightening encounter. I accidentally drove onto a snow bridge across a hidden crevasse. My quad stopped moving forwards and started to sink as the rotating wheels churned through the snow bridge. I was in a party of three at the time. We were about 30 metres from our work site, at a spot where we had spent several hours setting up a DORIS station. I heard the shouts of my companions ahead, telling me to try to reverse out of the slot. But reversing only aggravated my situation, and I realised that it was useless, as three of the quad's wheels had already penetrated the snow bridge, allowing me a disconcerting view into the depths of the icy blue chasm below. I cautiously stepped from the quad, to which I was roped, and braced myself for a fall.
It was some comfort to know that I was anchored by the two quads ahead of me. The other two members of the party walked cautiously back to my position and together we set up a pulley system to retrieve the precariously nestled quad. It was at this time that I learned why the quad had not fallen further, as I had expected it to. It had become wedged (by some good fortune) by the sled I was towing, in the mouth of the crevasse.
Ben Patrick looks into the depths of a crevasse
Grim encounters such as this, and I know others have experienced far worse, form a great part of the adventure of surveying in Antarctica. They are not experiences deliberately sought, but they must be dealt with when surveying in any glacial environment. To make matters more challenging, the Antarctic surveyor is often forced to work with only limited resources and with instruments that behave temperamentally in cold conditions.
Problems I have experienced with gear include laptop and GPS data logger failure, batteries running low more quickly than normal, tripods tilting as they settle into the glacier ice, the lack of nearby bedrock to provide suitable reference sites, and condensation.
Some of these problems are easily alleviated. For instance, to keep batteries warm, I learned to insulate them with clothing. To lessen the extent of tripod tilting on the glacier surface I devised small wooden platforms for the legs to sit on. This reduces pressure on the ice. It also helps if you bury the legs in snow to prevent them heating in the sunlight.
Another time a thin veneer of ice formed on the underside of the optical plummet lens on a tribrach. This proved an obstruction to the centring process when setting up a tripod, and caused me some confusion until I dislodged it with a pin.
Not all problems are so easily dealt with. I recall feeling that our situation was totally helpless when a power spike of 360 volts destroyed the transformer box of a laptop I was using to download and process the GPS survey data. For a short (and worrying) period there was a backlog of data on the GPS data loggers and I couldnÕt begin any further surveys. Fortunately there were communication technicians at Davis who were able to produce a new power supply for the laptop. It was an awkward contraption, made up of two gel cell batteries and a transformer tucked into a bulky wooden box Ð but it was lugged around with the portable computer ever after.
I have found that the most exciting aspect of surveying in Antarctica is coping with these problems. No matter how trivial, deriving new stratagems to get around them in an environment that is so physically demanding is a challenge. It is splendid.
Adrian F Corvino has recently completed a Bachelor of Geomatics/Bachelor of Science degree, majoring in Geology, at the University of Melbourne. He is currently working as a consultant at LICS (Land Information and Cartographic Services) in Melbourne, and will be returning to Antarctica in September 2002.
